Vinyl acetate is an important chemical commodity which is produced in plant scale volumes. In one commercial process for vinyl acetate production, a supply of ethylene, acetic acid and oxygen is passed in vapor phase contact with a palladium catalyst. The overall efficiency of the process is limited by the need to control the highly exothermal nature of the reaction.
An alternative type of reaction system for producing vinyl esters is proposed in U.S. Pat. No. 3,248,312 and a related U.S. Pat. No. 3,560,354 patent.
In the Example of U.S. Pat. No. 3,248,312, an electrolytic cell is provided which has two chambers separated by a porous membrane. The anolyte consists of anhydrous acetic acid and 0.03 weight percent palladium and 10 weight percent lithium acetate. The catholyte consists of one normal sulfuric acid. Carbon electrodes are employed. The electrolytes are heated to 240.degree. F. and a direct current voltage of 9.9 volts is applied to the cell to obtain a current density of 0.05 amperes per square centimeter of anode surface. The electrolytes are stirred while ethylene is fed into the anode chamber. Gaseous effluent from the anode chamber is collected in a condenser system as a liquid product mixture consisting of 23 percent vinyl acetate and 77 percent acetic acid.
The potential of electrochemistry as a viable route to vinyl esters such as vinyl acetate has merited continuing research effort.
Accordingly, it is an object of this invention to provide an improved electrochemical process for converting ethylene and acetic acid to vinyl acetate.
It is a further object of this invention to provide an efficient electrochemical process for vinyl acetate production under ambient conditions of temperature and pressure.
It is another object of this invention to provide an electrochemical process for anodic production of vinyl acetate from ethylene and acetic acid, wherein the electrolytic cell is operated at a constant potential.
Other objects and advantages of the present invention shall become apparent from the accompanying description and example.